Lens grinding machine



/ Aug. 18, 1942. V J. GASPARI LENS GRINDING MACHINE Filed May 29, 1940 2 Sheets-Sheet 1 l m a j W0 6 Mg Q MN M y L M I n w .6. ma M 65 w w m M v} a E T 4 7//% 2 vs 2 m@ I p a r J m w/ 4 7. 0 Z 7 mm a 5 J 3 2 M M 0 w m W. %I i a w 9 I Patented Aug. 18, 1942 LENS GRINDING MACHINE Joseph .Gaspari, Harrison, N. Y., assignor to- J. Gaspari &. 00., 1110., New York, N. Y., a corporation of New York Application May 29, 1940, Serial No. 337,741

4 Claims.

This invention relates to improvements in grinding machines and has particular reference to a machine for grinding ophthalmic lenses.

It has been proposed, heretofore, to form a groove in the periphery of a lens in which is countersunk the eye wire of an eyeglass frame, whereby said wire is, at least, partially invisible so as to give the appearance of a rimless frame. The problem of forming such a groove in the periphery of a circular lens, whether it be toric or flat, is a relatively simple one since it merely involves the rotation of a lens in a fixed plane and in contact with a cutting or grinding element. However, certain difficulties are encountered when grinding a lens of perimetrically irregular formation. These difficulties reside primarily in the fact that as the edge of such a lens is presented to a cutter and gradually rtated, the variations in the radii of said lens necessitate a relative lateral shifting between said lens and the cutter so as to maintain the latter in constant engagement with'said-edge during a complete rotation of the lens.

A featureof the present invention resides in the provision of an improved grinding machine of simple and practical construction wherein a Work holder is supported relative to a cutter element in such manner that as the periphery of a lens in said holder is. being ground by a cutter said element will be maintained in constant peripheral engagement irrespective of the perimetric contourof said lens.

Another feature is to mount the work holder for movement toward and away from the cutter and also laterally relative to the plane of the latter so that as the distance from the center of a perimetrically irregular lens to the edge thereof-varies, during rotation of the lens relative to the cutter, said edge will be constantly maintained in contact with said cutter.

The inventive idea involved is capable of receiving a variety of mechanicalexpressions some of which, for purposes'of illustration, are shown in the accompanying drawings wherein- Figure 1 is a top plan view of a grinding machine constructed in accordance with the invention.

Figure 2 is a front elevation thereof, partly broken awayand' shown in section;

Figure 3 is a vertical section'on the line 3-3 of Figure 2.

Figure 4 is a section on the line 4-4 of Figure 1.

Figure-5 is a section on th'e line 5-5 of Figure 4-.

Figure 6 is a perspective view of a gage utilized in controlling the grinding operation upon the lens.

Figure 7 is a diagrammatic view illustrating a range of lateral movement of the edge of a erimetrically irregular lens as the same is rotated relative to a cutter which forms agroove in the periphery of the lens.

Figures 8 and 9 are plan views of different types of perimetrically irregular lenses, and

Figure 10 isa fragmentary section through a toric lens of the type shown in Figures 8 and 9.

The machine is shown in its preferred form as comprising the standard H carrying at its upper end the bearing H for a shaft l3 driven from any suitable source of power by a belt and pulley 14 connected to one end of said shaft. At the opposite end of the shaft the same carries a disklike cutter element 15 which may be made of any abrasive material suitable for cutting or grinding glass.

Adjacent the base of the standard H there is provided a pair of bearings it for receiving the ends of a rod ll. This rod supports a frame [8 for rocking movements toward and away from the cutter l5, and also for movements longitudinally of said rod whereby said frame and the parts carried thereby may be shifted laterally relative to the plane of the cutter. Supported between intermediate portions of the frame I8 at its upper end is a pair of jaws I9 and 29 each recessed to receive a ring-like resilient support 2| disposed in opposed relation to the support carried by the other jaw for the purpose of clamping a lens 22 therebetween, with said supports 2| engaging the approximate center of the lens. The jaw I9 is provided with a shaft 23 having a bearing in the frame I8 and formed with a handle 24 at its outer end by means of which the shaft 23 may be turned by hand to rotate the lens 22 relative to the cutter 15. The jaw 29 has a shaft 25 also mounted in the frame I8 and provided with a screw threaded portion 26 engageable with said frame so'that when said shaft 25 is turned by means of its handle 21, the jaw 20 may be adjusted toward and away from the jaw l9 to clamp the lens 20 between the supports 2| and to release said lens therefrom. In order that the portion of the jaw 20 which carries the support 2| may be rotated with the jaw [-9 as the latter is turned by the shaft 23, a ball bearing race 28 is provided for the jaw 29 which permits the outer portion of said jaw to rotate relative to the inner portion thereof in which the shaft 26 is fixed.

In order to maintain the periphery of the lens 22 in engagement with the edge of the cutter l5 during the grinding operation, means are provided for exerting a pull upon th'e frame [8 in the direction of the standard II, as best shown in Figure 3. Said means consists of a retractable spring 29 having one end connected to the standard II and its other end to an elongated plate 30 that extends through the lower portion of the frame l8. In said portion of the frame, there is provided a pin 3| which extends through a slot 32 in the plate 30, said slot being curved at one end to provide a recess for receiving the pin 30 when the plate is pulled outwardly from the frame l8 to place the spring 29 under tension. When so tensio'ned, the spring exerts a pull upon the frame l8 in the direction of the standard ll so as to yieldably maintain the periphery of the lens 22 in contact with the cutter I5.

It will be understood that if the lens 22 were circular in formation, the engagement of its edge with the cutter by rocking movement of the frame l8 would be sufficient to maintain the lens and cutter in the necessary position for having a groove formed in the edge of the lens by the relative rotation of said cutter and lens. However, when a toric lens of perimetrically irregular formation is to be ground, it will be apparent, as shown diagrammatically in Figure '7, that as said lens is rotated the plane of its edge will shift laterally in accordance with variations in the radii of the irregular contour of the lens. Therefore, in order to constantly maintain the edge of the lens in engagement with the cutter l5, this lateral shifting of said edge must be compensated for by a corresponding movement of the lens holder which includes the frame l8 and jaws I 9 and 20. To this end, there is provided a gage block 33 adjustably secured to a support 34 which mayiorm a part of the standard I I and which may be provided with an extension 35 recessed within one corner of the block 33. The retention of the block 33 in an adjusted position relative to the support 34 is accomplished by means of a screw 33 which extends downwardly through a slot 3'! in said block and into the support 34. A screw bolt 38 extending through the front of the block 33 and into the extension 35 of the support 34, provides a means whereby a slight adjustment of the block on the support may be accomplished. This adjustment is made as a preliminary step in the adjustment of a gage element 39 carried by said block 33. This element 39 comprises an elongated substantially rectangular section which is recessed in a groove 40 in the block 33, and said section is adjustable longitudinally in said recess and held in its adjusted positions by means of a screw 4| extending horizontally through a slot 42 formed in the block 33. At one end of the gage section 39 the same is provided with angularly disposed portions 43 and 44 the former of which is adapted to engage the convex face of the lens 22 as shown in Figure l. The arcuate face 45 of the portion 44 is adapted for contact with the periphery of said lens so as to act as a stop therefor to prevent movements of the lens toward the cutter [5 under the influence of the spring 29, thereby to control the depth of the groove 46 to be cut in the edge of said lens. By adjusting the screw 38 to move the block 33 and the gage element 39 in a radial direction with respect to the cutter l5, it will be obvious that the depth of the groove to be formed on the lens may be regulated.

Cooperating with the gage element 39, is a guide 41 slidably mounted in a bearing 48 and having a spring 49 coiled thereabout so as to exert a yielding pressure upon said guide in the direction of the lens 22 whereby the inner end of the guide 41 will be maintained in constant contact with the inner or concave surface of said lens at a point substantially opposite the gage portion 43. After the various adjustments of the gage have been accomplished to properly position the lens 22 for contact of its periphery with the edge of the cutter I5, the rotation of the cutter is started, and the lens 22 is turned by manual manipulation of the handle 24 which imparts rotation to the shaft 23 and the jaws I9 and 20. The gage 39 and the guide 41 act to maintain the periphery of the lens in engagement with the cutter, and as said lens is turned and the radius at the point of contact thereof varies, the spring 29 will act to continuously maintain the contact between the lens and cutter, and the gage 39 will effect any necessary lateral shifting of the lens relative to the cutter to maintain said peripheral engagement, such shifting of the lens being transmitted to the frame [8 which slides on the rod l1.

What is claimed is:

1. A machine for forming a groove in the periphery of a lens, comprising a cutter, a lens holder, means to rotate said holder, means to support one of said elements for movements in different planes relative to the other, a gage having portions contacting the periphery and other portions contacting one face of said lens for controlling said movements, and a yieldable guide contacting the other face of said lens during said movements.

2. A machine for grinding the periphery of a toric lens of perimetrically irregular formation, comprising a cutter, a lens holder, means to rotate said holder, a support for said holder with respect to which the holder is movable toward and away from said cutter having a portion contacting the periphery of the lens for controlling the movement of the holder toward and away from said cutter, and another portion contacting one face of said lens for controlling said movement laterally relative to the plane of said cutter and a yieldable guide contacting the other face of said lens during said movements.

3. In a machine for cutting a groove of predetermined depth into the edge of a lens, said groove being spaced a predetermined distance from one face of the lens, a grinding wheel, a rotatable lens support for presenting the edge of a lens to the grinding wheel, said support being mounted for movement toward and away from said grinding wheel and for movement laterally of the plane of said wheel, and means for controlling said movements, said means comprising a gage block mounted so as to be adjustable in a direction substantially parallel to the plane of said wheel, and a gage element mounted on said gage block so as to be adjustable in a direction substantially parallel to the axis of said wheel, said gage element being provided with a portion adapted to engage the edge of a lens and with another portion adapted to engage one face of the lens, a guide for engaging the other face of said lens opposite said face-engaging portion of said gage element, a mounting for said guide whereby it is movable toward and away from said lens, means for urging said guide into engagement with said lens face, and means for urging said lens support toward said grinding wheel.

4. A machine for grinding a groove in the periphery of a toric lens of perimetrically irregular conformation, comprising a rotary cutter,

a supporting rod, a frame swingable on said rod in a direction toward and away from said cutter and also movable longitudinally of said rod, a lens holder carried by said frame, means to rotate said holder relative to said frame and cutter, means to maintain the periphery of said lens in yielding contact with said cutter, a gage having a portion for contacting the lens-edge and another portion for contacting one face of the lens, a

mounting for said gage whereby it may be independently adjusted relative to said cutter for predetermining the depth of cut of the cutter and for predetermining'the distance of the cut from one face of the lens, and a spring-controlled guide engaging said lens opposite said face-contacting portion.

JOSEPH GASPARI. 

